The Helicobacter pylori infection is the main factor of risk for gastric cancer, in the immune response induced for the bacterium there is an infiltration of cells which produce high levels of cytokines, which may be involved in gastric carcinogenesis. The objetive of this investigation is to evaluate the relation of the expression of IFN- γ and IL-4 with the H. pylori infection, chronic gastritis and gastric cancer. 100 patients with chronic gastritis and twenty with gastric cancer were included; the expression of INF-g and IL-4 was determined by immunohistochemistry. 57.5% of cases were positive for H. pylori, the highest frequency of IFN- γ expression was found in cases of cancer H. pylori-positive, in the case of IL-4 was more frequent in patients H. pylori-positive with chronic gastritis. The IFN- γ expression frequency was higher than the IL-4 expression. In the majority of the samples H. pylori-positive were expressed the two cytokines.